Re: [PATCH v2 4/5] Makefile: use the sha1collisiondetection submodule by default

[Junio C Hamano <gitster@pobox.com>]

Junio C Hamano <gitster@pobox.com> writes:

> That endgame allows us not force people to grab an essential part of
> the codebase as an external dependency from another place, which
> feels quite bad, especially when their primary interest is not in
> dogfooding submodule but in building a working version of Git.
>
> Removing one and keeping the other between the two will make the
> distribution more streamlined by removing the build-time knob we
> need to tweak, but the one that gets removed does not have to be the
> in-tree one that allows people to "git clone" from just one place.

Perhaps this may deserve a bit more explanation.

I wouldn't be so against "let's do submodule-only" if this were not
SHA-1 implementation but something like gitk and git-gui.  An optional
part of a system that it is safe to leave to individual builders if
they want to fetch and use that part *is* an ideal target to bind as
a submodule to the system.

It's just the "default SHA-1 implementation" is at the far opposite
end of the spectrum from "an optional part", and our use of
submodule to bind this code is definitely *not* because it makes
sense to use submodule in that context; it is because developers
(not necessarily those who consume Git sourcecode) *wanted* to use
submodule there, regardless of the real merit of doing so.

And that is why I do not feel entirely happy with the step 4/5 and
also I feel moderately strongly against the step 5/5.  These two
steps have a "developer first" smell that disgusts me.